1. Field of the Invention
The present disclosure relates to the automated focusing and collimation of optical devices such as, for example, telescopes.
2. Description of the Related Art
Astronomy, and in particular, optical astronomy is increasingly popular, and advancements have been introduced in recent years to the instruments used for astronomical observation. High performance optical telescopes for the amateur and more advanced enthusiasts may include, for example, diffraction limited optical systems offering high resolving power as well as CCD cameras for recording vivid images. Such telescopes may have accurate computer controlled drive systems for positioning the telescope using databases of deep-sky objects, stars, objects in our solar system and even earth satellites. With such sophisticated equipment to assist the astronomer, astronomy can be wonderfully enjoyable while the images obtained can be impressive and awestriking.
Proper focusing and collimation are important for quality imaging. Telescopes are designed to collect substantially collimated light from distant objects in the sky and to focus the light onto a focal plane. In a Cassegrain telescope, light is collected by a large primary mirror and reflected toward a secondary mirror, which reflects the beam of light to the focal plane. (The primary mirror may alternatively be referred to herein as the primary, while the secondary mirror may alternatively be referred to herein as the secondary as is customary in the art.) The curved primary and secondary mirrors focus the beam onto the focal plane where an ocular or camera may receive the light for viewing or recording an image. The optical system, comprising the primary longitudinally displaced along an optical axis a distance from the secondary mirror, has an effective focal length, which is determined in part by this longitudinal separation. The longitudinal distance separating the primary and secondary may be adjusted to alter the location where the images come to focus. Conventional telescopes are focused by translating the primary mirror such that a sharp image is formed at the desired image plane.
Proper orientation of the mirrors with respect to the optical axis and to each other is also important for quality imaging. Misalignment in the form of tilt of the primary or secondary may result in image distortion.